function upload(file, posturl, name)
{
  var boundary = "--------XX" + Math.random();

  var req = new XMLHttpRequest();
  req.open("POST", posturl);
  req.setRequestHeader("Content-type", "multipart/form-data; boundary=" + boundary);
  req.setRequestHeader("Content-length", file.fileSize);
  req.onload = function(event) { alert(event.target.responseText); }

  var prefix = "--" + boundary + "\n" +
               "Content-Disposition: form-data; name=\"" + name + "\"; filename=\"" +
               file.leafName + "\"\n" +
               "Content-type: text/plain\n\n";
  var stream = IO.newInputStream(prefix, "multi");
  stream.appendStream(IO.newInputStream(file, ""));
  stream.appendStream(IO.newInputStream("\n--" + boundary + "\n", ""));

  req.send(stream);
}